There are some systems available today for adaptive front-lighting of a vehicle. These systems seek to provide dynamic front lighting, or curve lighting functionality, for a vehicle and may be commercially available under the names “Adaptive Front-Lighting System” or “Advanced Front-Lighting System” (“AFS”).
The systems that are currently available may typically use mechanical systems to provide the curve lighting functionality. For example, motors, such as stepper motors, may rotate a lens, a reflector, a mount, or a light source of a headlamp, or an entire light module. The stepper motors may receive signals to steer the light beam in horizontal and/or vertical directions. A particular steering angle of the light beam may be defined as a function of vehicle speed and steering wheel angle. In addition, a typical range of rotation of the light beam may be ±15 degrees left/right and ±15 degrees up/down. As a result, a roadway may be much more effectively illuminated by the curve lighting functionality, thereby increasing safety and comfort.
FIG. 1 shows a schematic view of a conventional system 1 for adaptive front-lighting of a vehicle. The system 1 includes a low-beam light source 2, a high-beam light source 3, and a side marker light source 4. According to the system 1 for adaptive front-lighting, the low-beam light source 2 may be rotated about the Z axis, in order to change the horizontal steering angle of the light beam, and the low-beam light source 2 may also be rotated about the X axis, in order to change the vertical steering angle of the light beam. These rotations may be effected by motors, such as stepper motors, for example.
The system 1, as shown in FIG. 1, is of a left side headlamp; however, it should be understood that a right side headlamp would be a mirror image of FIG. 1.
FIG. 2 shows a schematic top view of a lighting distribution using a system 1 for adaptive front-lighting of a vehicle. This Figure illustrates a driving situation in which the vehicle is driving along a roadway curving towards the left. In a vehicle without a system 1 for adaptive front-lighting, a standard light distribution 5 having a center axis 6 may be projected forward of the vehicle. This standard light distribution 5 cannot be changed because the vehicle lacks adaptive front-lighting.
However, in a vehicle having a system 1 for adaptive front-lighting, an angled light distribution 7 having a center axis 8 may be projected forward and to the left side of the vehicle. By rotating the low-beam light source 2 about the Z axis towards the left side of the vehicle, the angled light distribution 7 may be projected in order to increase driver safety and comfort. As shown in FIG. 2, the low-beam light source 2 has been rotated an angle β towards the left side of the vehicle, for example. The angle β may be defined based on, for example, a vehicle speed, a steering wheel angle, road characteristics, etc.
The angled light distribution 7 of the system 1, as shown in FIG. 2, is angled towards the left side of the vehicle for the driving situation in which the vehicle is driving along a roadway curving towards the left. However, it should be understood that a similar angled light distribution of the system 1 may be angled towards the right side of the vehicle for the driving situation in which the vehicle is driving along a roadway curving towards the right.
FIG. 3 shows a schematic block diagram of a conventional system for controlling adaptive front-lighting of a vehicle. The control system may include a system left headlamp 1, a system right headlamp 1, a control unit 9, and input data 10. Input data 10 may include vehicle data, such as, for example, vehicle speed, steering wheel angle, road characteristics, etc. Input data 10 may be fed into the control unit 9, which then controls each of the system left and right headlamps 1 to steer the light beam.
However, these mechanical systems having moving parts may present many technical challenges, such as space, weight, and quality constraints, for example. In particular, the moving parts must be designed so that they do not collide with other components in the headlamp. Also, the moving parts require additional mechanical structure and motors, which may add unwanted weight to the headlamp. In addition, the moving parts may create quality issues, such as disconnected cables, or other overall malfunctions of the headlamp, for example.
Accordingly, it may be desirable to have a system that achieves dynamic front lighting, or curve lighting functionality, without moving parts. There have been some proposals to achieve such dynamic front lighting without moving parts. However, the proposed systems require advanced technology and/or advanced production capability, thereby adversely affecting both cost and feasibility.
German Published Patent Application No. 10 2005 014 953 describes a vehicle having a matrix of LEDs for forward illumination, and a control device that detects an oncoming vehicle on a road and steers, switches off, dims, or covers by a diaphragm, an LED directed at the detected oncoming vehicle.
German Published Patent Application No. 10 2006 039 182 describes a vehicle having a light radiating device with two or more LED segments, and a control device to vary the emitted radiation intensity of the LED segments.
U.S. Patent Application Publication No. 2007/0003108 describes a system having a plurality of light emitting diodes (LEDs) arranged in a matrix in order to achieve both vertical and horizontal light steering. However, heat management and cost may be challenges with such a system because the accuracy of such a system is directly proportional to the number of LEDs utilized.
Also, BMW is believed to have proposed an adaptive front-lighting system that is referred to as “Pixel Light.” In this system, micro mirror devices each reflect one pixel of a light beam. Further, the light beam is fixed in place but can be programmed to suit the conditions in front of a vehicle.
PCT International Published Patent Application No. WO2007/122544 describes a system that places a liquid crystal element in front of a light source in order to steer the light beam.